lawsuits has kept many design engineers from using the gas-assist process for
injection molded parts. Gas-assist molding was a way to reduce the weight of
thick parts, improve the surface finish and reduce costs.
reason to be afraid anymore, however, according to Cinpres Gas Injection, which
says it has reached agreement to buy patents from the liquidator of Melea Ltd. Melea's
patents were marketed by a company called Gain Technologies, which had threatened
legal action against competitive technologies.
16 years attempting to prevent Melea from claiming ownership of the patent for
a technique described as "spillover," a process that prevents sink and weld
marks in hollow plastic objects. James Hendry, the inventor of the process, worked
for both companies at different times.
owner, Michael Ladney, maintained that Hendry invented the process while
working for Melea. In an English trial several years ago, Hendry testified for
Melea, then admitted perjury and supported Cinpres' case, according to an account
on Cinpres' website. A Court of Appeal ruling in 2008 backed Cinpres, leading
to the collapse of Melea.
In a new press release
, Cinpres Managing Director Jon
Butler says, "There can now be no further confusion - Cinpres will be the
undisputed owner of all the appropriate gas-assisted technologies. Customers
can now buy our technologies without fear of contested claims and
counter-claims between Cinpres and Melea, or any other party."
Injection describes itself as the world's leading company in gas-assisted
molding (GAM) technology and says it is the only company in the world licensed
to sell the plastic expulsion process (PEP) and external gas molding (EGM).
resolution of the legal case likely will allow significant expansion of the
for design engineers because molded products are no longer restricted to certain
basic design rules such as boss and rib size relative to wall thickness.
injection molding is defined as a process that uses nitrogen or another inert
gas to create hollow channels within a part. Channels are designed into the
part, improving strength and speeding cycle times. Flow channels may also
eliminate the need for hot runners. Tubular sections can be designed into the
product and eliminate the need for expensive undercuts and lifters in the tool.
Most thermoplastics can be used in the process.